I am sorry there is no edit so I added this information to a reply. 51.0.1 is my current version I just did a restore back to find it and it restores all tabs just fine again.

Do you have any special non ASCII characters (i.e. UTF-8 or quotes) in the profile path?

You can check the path on the about:profiles page.

You can open "about:" pages via the location/address bar

• "about:" is a protocol to access special pages

there is only one profile and it has a path; C:\Users\Eric Sasavicz\AppData\Roaming\Mozilla\Firefox\Profiles\wi3zh4j5.default Another very strange thing my other laptop is on 55.0.3 and if I put the sessionstore file from this laptop (the one that will not restore upon updating) into that firefoxs correct folder BAM it loads all my tabs.

Did you check the startup setting?

• Options/Preferences -> General -> Startup: "When Firefox starts":
  "Show my windows and tabs from last time"

Yes I mentioned that in the original post.

Anyone else have any ideas?

Does Firefox create a sessionstore.js when you close Firefox?

Did you check your sessionstore.js file in a text editor or Firefox tab to make sure the file isn't corrupted?

See also this website of SUMO contributor JScher2000:

• https://gist.github.com/jscher2000/07f94249b0a5f6d565fb20d88b73bb91

I answered this in the first post. It creates no sessionstore.js when it closes. If I put a known working sessionstore.js in and open firefox it does not load it and deletes it.

You aren't running Firefox in Private Browsing mode or clear the browsing history when you close Firefox as this would prevent restoring the session?

Do you see the other files in the sessionstore-backups getting updated?

You will normally find these files in the sessionstore-backups folder:

• previous.js (cleanBackup: copy of sessionstore.js from previous session that was loaded successfully)
• recovery.js (latest version of sessionstore.js written during runtime)
• recovery.bak (previous version of sessionstore.js written during runtime)
• upgrade.js-<build_id> (backup created during an upgrade of Firefox)

You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.js to replace the current file (make a backup copy of the current sessionstore.js).

See also:

• http://www.ghacks.net/2014/06/27/mozilla-launches-improved-session-restore-firefox-33/

I am not in a private window and have nothing set to clear. No settings were changed from a working 51.0.1 I just let it update to the 55.0.3 via the pop up that comes up and asks me to update. Both my gaming rig and home server are running a 47 build (I don't browse the web much on them) when they update they both no longer open up tabs from last session. They currently open tabs and no settings are changed as I try the update.

Are you using your current profile with multiple Firefox versions or do you have a separate profile for each Firefox version in case you have more than one Firefox version installed?

Note that you should always use a separate profile for each Firefox version.

I only have one profile. I only have one version of firefox until I tried to update and it failed and I just copied folders back and made it the old version again. It was already talked about above and I didn't know about multi profiles before this thread. I only have one version of firefox running at any time I have no idea how to run multi. I can completely uninstall firefox from these pc's and delete all folders and install a new version and it will not do nay session restore. The above link was to a 33 version and I am on some 47 and 51 version that is working before the upgrade to this 55 version.